*5.3.1. Candida*

Species of *Candida* are commonly associated with the mucous membranes of animals in limited numbers, and occur predominantly in the regions of the blowhole, oesophagus, vagina and anal area in cetaceans [59-61]. *Candida* spp. reported from cetaceans include *Candida albicans, Candida glabrata, Candida krusei, Candida tropicalis, Candida parapsilosis, Candida guiliermondii*, *Candida lambica* and *Candida ciferrii* [59, 60]. *Candida zeylanoides* was also found to be associated with the skin of a southern right whale neonate from South Africa [45]. Infections caused by *Candida* spp. mostly affect captive cetaceans and are usually associated with immuno-suppressed individuals, where the *Candida* infection may proliferate and cause severe local infection of the skin or mucosal membranes. In captive cetaceans, infections are usually observed after long-term antibiotic therapy [30, 61], but had also been reported following corticosteroid treatment of the animals, as well as after overtreatment of tank water [59]. These lesions usually occur as whitish, creamy plaques on the skin or mucosal surfaces. Histological examinations usually show colonies of pseudohyphae, septate hyphae and blastospores [16, 60].

Cutaneous Lesions in Cetaceans: An Indicator of Ecosystem Status? 137

case of this disease in a Guinana dolphin. Interestingly, no other cetaceans other than dolphins have ever been reported with this disease [59, 60]. It is generally accepted that the disease is the consequence of injuries sustained by the animal [61], and can therefore be transmitted to humans during necropsies [58]. It presents itself as white, elevated, crusty, nodular lesions on the animal's body [59-61], although mainly on the head, flippers, abdomen, fins, back tail stocks and flukes [60]. On cellular level, the disease presents with superficial granulomatous dermatitis, associated with macrophages and multinucleated giant cells containing a variety of round yeast cells [61]. More cases of this disease affecting cetaceans have been added to the list and recently some authors suggested that the incidence of lobomycosis might represent opportunistic infections in immuno-compromised hosts [62, 65]. The bio-accumulation of environmental contaminants in the affected dolphins

Dermatophytes are fungi that grow on the outermost layers of the skin of animals, including muco-cutaneous membranes, genitalia, external ears, as well as dead skin or hair. Ringworm presents one type of dermathophyte and includes the genera *Tinea, Trichophyton, Epidermophyton* and *Microsporum* [16]*.* Infections caused by dermatophytes, seem to be rare in marine mammals, and therefore also in cetaceans. Limited reports include discrete nodules on

the back of a captive Atlantic bottlenose dolphin caused by a sp. of *Trichophyton* [60].

**6. Marine pollution and the impact of industrialization on cetaceans – A** 

Rapid population growth and industrialization have characterized urban development. However, the rate of population growth is far higher than the rate of waste and wastewater infrastructure planning and development [1, 66]. This phenomenon has led to ever increasing pressure on natural resources and the creation of massive volumes of waste and waste water [67]. Marine pollution had been defined as deleterious effects resulting, either directly or indirectly, from the introduction of substances or energy by humans to the marine environment [66]. High levels of marine pollution especially along urban areas, pose a serious threat to the health of humans, as well as marine mammals. Although numbers of cetaceans have markedly improved over the past few years as a result of conservation efforts, the quality of the habitat in and near bay areas are critical, because these areas are used by these marine mammals for feeding, mating and calving [1]. Waste entering the marine environment had been categorized into the following groups of activities [68]:

 Waste from land-based sources such as sewage and industrial effluent discharges, storm-water run-off, agricultural and mining return flows, as well as seepage from contaminated ground water. These account for the highest percentage of waste to enter

Atmosphere pollutants, including persistent organic compounds from vehicle exhausts

was thought to possibly contribute to susceptibility to this disease [62].

*5.3.4. Dermatophytes* 

**possible cause?** 

the sea environment.

and industries.

In cutaneous *Candida* infections, the skin or mucosal membranes, may suffer acanthosis (hyperplasia and thickening of the stratum spinosum) with pseudoepitheliomatous hyperplasia, with the fungus growing in the epithelial tissue. These cutaneous *Candida*  infections had been reported in a number of cases pertaining to especially captive cetaceans and varied from ulcerative dermatitis, to inflammation without ulcers and healed ulcers. However, significantly more cases of visceral lesions and systemic candidiasis had been reported in these mammals [60].
